detecting a config file should look in the specified data dir

[nahuhh]

1. Insert a bitmonero.conf into the default datadir
2. Run monero wirh ./monerod = the ~/.bitmonero/bitmonero.conf if used
3. Add a bitmonero.conf into a folder called bitmonero2
4. Run ./monerod --data-dir bitmonero2 = the bitmonero.conf from ~/.bitmonero is used instead.

expected: the config source datadir should not be static, and should 1st check --config-file, 2nd check --data-dir.
Only In absence of --data-dir and --config-file should it look in the default datadir